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Notes: Objective: The purpose of this study was to evaluate the effects of self-etching primer drying times on the bond strength of resin to bovine enamel. Materials and Methods: Three self-etching primer adhesive systems–Imperva Fluoro Bond® (Shofu Inc., Kyoto, Japan), Clearfil® Liner Bond (Kuraray Co. Ltd., Osaka, Japan), and Mac Bond® II (Tokuyama Corp., Tokyo, Japan)– were used in this study, The labial enamel surfaces of bovine incisors were exposed by grinding with 240-grit and 600-grit wet silicon carbide paper. The primers were applied to enamel surfaces as per manufacturers' instructions. After priming, the surfaces were dried with compressed air for 0, 2, 5, 10, 20, or 30 seconds from 10 cm above the surface using a three-way syringe. Following the application of adhesive resin, resin composites were applied into molds (diameter = 4 mm, depth = 2 mm) and were light-cured. The shear test was performed at a crosshead speed of 1.0 mm/min. The ultrastructure of resin-enamel interfaces was observed with SEM at magnifications of 2,000× to 3,500×. Results: Mean enamel bond strengths varied with the different drying times and ranged from 8.2 to 17.4 MPa for Clearfil Liner Bond, from 10.9 to 16.3 MPa for Imperva Fluoro Bond, and from 17.5 to 19.4 MPa for Mac Bond. For Clearfil Liner Bond and Imperva Fluoro Bond, mean bond strengths increased significantly at the 10-second drying time, whereas Mac Bond did not experience a significant change in bond strengths. SEM examination revealed morphologic differences among the groups with varying drying times. Resin tag penetration was not clearly seen at the 0-second drying time, but resin tags appeared to be intimately adapted to the enamel surface in specimens at the 30-second drying time. Conclusions: The drying time of the self-etching primer prior to the application of bonding resin affected the shear bond strength of resin to enamel for two self-etch adhesive systems.

Notes: Objective: The purpose of this study was to determine the effect of thermal cycling on the enamel bond strengths of two-step adhesive systems, either self-etching primers or “one-bottle” total-etch systems, to bovine enamel. Materials and Methods: Three self-etching primer systems–Imperva Fluoro Bond® (Shofu Inc., Kyoto, Japan), Clearfil® Liner Bond II (Kuraray Co. Ltd., Osaka, Japan), and Mac Bond® II (Tokuyama Corp., Tokyo, Japan)–and four total-etch adhesive systems–One-Step® (Bisco Inc., Schaumburg, IL, USA), Opti-Bond Solo® (Kerr Corporation, Orange, CA, USA), Prime & Bond® 2.0 (Dentsply DeTrey, Konstanz, Germany), and Single BondTM (3M ESPE, St. Paul, MN, USA)–were used. Labial enamel surfaces of bovine incisors were exposed by grinding with 240-grit and 600-grit wet silicon carbide paper. Enamel was treated according to the manufacturers' instructions. Following the application of adhesive resin, resin composites were condensed into a mold (diameter = 4 mm, depth = 2 mm) and were light-cured. Bonded specimens were stored in 37°C water for 24 hours. They were divided into a control group (no thermal cycling) and three experimental groups with thermal cycles of 3,000, 10,000, and 30,000 cycles, respectively, between 5°C and 60°C. The shear test was performed at a crosshead speed of 1.0 mm/min. The ultrastructure of resin-enamel interfaces was observed by SEM at times 3,500 magnification. Results: Self-etching primer systems had significant decreases in enamel bond strengths with thermal cycling. In contrast, total-etch systems had no significant differences, except for One-Step. Mixed failures were predominant in these systems, but adhesive failures tended to increase with a greater number of thermal cycles. SEM observations revealed small cracks at the resin-enamel interface for self-etching primer systems when subjected to 30,000 thermal cycles. Conclusions: Enamel shear bond strengths after thermal cycling of self-etching primer systems appeared to be less stable than were those of total-etch adhesive systems.

Notes: Background In vitro-derived human mast cells exhibit different properties, depending in part on the source of progenitor cells. Most investigations have used fetal liver, cord blood or peripheral blood. Few have used adult bone marrow.Objective Human mast cells derived in vitro from the CD34+ progenitors in bone marrow and cord blood that had been cultured with recombinant human stem cell factor (rhSCF) and recombinant human interleukin-6 (rhIL-6) were compared.Methods and results After 12 weeks of culture, nearly all of the cells were mast cells, and nearly all of these had cytoplasmic granules containing both tryptase and chymase (MCTC type), stained metachromatically with acidic toluidine blue, and expressed CD117 on the cell surface. Both tryptase protein and mRNA were detected by two weeks of culture. Chymase mRNA and protein were detected at 4 weeks but not at 2 weeks of culture. By 12 weeks, chymase content per cell, measured by ELISA, was significantly higher (P 〈 0.05) in human bone marrow-derived mast cells (HBMMC) (5.6 ± 0.9 pg) than in cord blood-derived mast cells (CBMC) (2.4 ± 0.9 pg), whereas histamine and tryptase levels were not significantly different. Of the cluster designations tested, CD29, CD49d, CD51 and CD61 were strongly expressed on HBMMC. CD54 and FcεRIα also were expressed constitutively. Approximately half of CD34-sorted cells at day 0 were CD13+ and this diminished as mast cell maturation occurred. Electron microscopy revealed that 12-week-old HBMMC had many secretory granules that contained spherical electron dense cores surrounded by electron lucent space, consistent with previous reports of immature MCTC cells developing in vivo.Conclusions CD34+ progenitors of human bone marrow are a rich source of mast cell progenitors capable of expressing granule and surface markers of mature mast cells in the presence of rhSCF and rhIL-6.

Notes: The inhibition of angiotensin II (AngII) by use of angiotensin converting enzyme (ACE) inhibitor or AngII receptor blocker is effective for prevention of the progression of renal diseases including IgA nephropathy (IgAN). AngII plays a variety of biological roles via AngII receptors. Through AngII type 1 receptor (AT1R), AngII induces vasoconstriction, cellular proliferation, extracellular matrix production and fibrosis, while it leads vasodilatation, apoptosis and inhibition of cell proliferation through AngII type 2 receptor (AT2R). Recent studies showed the local production of AngII in many tissues including the heart, vessel and kidney, suggesting that local AngII may be more important than circulating AngII in tissue injury. AngII is generated from angiotensin I by ACE or ACE independent pathway, such as chymase which is a serine protease. Since chymase was shown to be synthesized 80% of AngII in human heart, chymase also may play an important role in converting to AngII in the kidney. Although it was reported that ACE was produced in renal tissue, the localization of chymase and AngII receptors is unclear in the human kidney. To research the local renin-angiotensin system in renal tissue of patients with IgAN, we localized chymase mRNA, ACE mRNA, AT1R mRNA and AT2R mRNA by in situ hybridization and investigated the relationship between the expression of these mRNAs and tissue injury. Fresh frozen sections of renal tissue from 21 patients with IgAN were examined. The sections were fixed with 4% paraformaldehyde and hybridized with the digoxigenin (DIG)-labelled oligonucleotide probes for chymase mRNA, ACE mRNA, AT1R mRNA and AT2R mRNA. Using anti-DIG antibody, immunohistochemistry was performed to visualize the DIG-labelled probe. Colour was developed by reaction with H2O2 and 3,3′diaminobenzidine/=tetrahydrochloride. As identifying the exact locations of the cells positive for chymase mRNA, ACE mRNA and AngII receptor mRNA, we stained using periodic acid-Schiff after in situ hybridization. We classified the histological grading of the glomerular and tubulointerstitial injury. Two to five glomeruli were analysed in each biopsy tissue and the degree of injury in each glomerulus was graded from 1 to 3 based on the proportion of the lesion in the sectioned areas of each glomerulus. In the tubulointerstitium, three to five fields of cortical interstitium in each section were examined under low magnification (×200). In each designated field, we determined the degree of tubular atrophy and interstitial fibrosis from grade 1 to 3. In situ hybridization showed that the signals of chymase mRNA, ACE mRNA, AT1R mRNA and AT2R mRNA were observed in mesangial cells, glomerular epithelial cells, cells of the Bowman’s capsule, cells of crescent, tubular epithelial cells and some infiltrating mononuclear cells. In the glomeruli, the percentage of cells positive for chymase mRNA, ACE mRNA, AT1R mRNA and AT2R mRNA per glomerulus decreased as the glomerular injury progressed. Chymase mRNA and ACE mRNA were diffusely expressed in the glomeruli with mild injury. The expression significantly increased in the area of mesangial cells proliferation without mesangial matrix expansion, however, it decreased as the glomerular lesion progressed. In the tubulointerstitium, the expression of chymase mRNA, ACE mRNA and AT1R mRNA positively correlated with the degree of tubulointerstitial injury. The expression of AT2R became significantly strongest in moderate injury lesions and diminished in severe lesion. All mRNAs were highly expressed in atrophic tubuli. We also examined the relation of the cells positive for chymase mRNA and ACE mRNA on serial sections. Most cells positive for chymase mRNA also stained for ACE mRNA in the glomeruli and the tubulointerstitium. In situ hybridization for AT1R mRNA and AT2R mRNA in serial sections showed that some cells produced the both mRNAs, while other cells expressed only AT1R mRNA or AT2R mRNA. In the present study, we identified that chymase, ACE and AngII receptor were synthesized in renal tissue with IgAN. Our results suggest that AngII was generated by local ACE and ACE independent pathway (chymase) and that the regulation of local renin angiotensin system in renal tissue was different between glomerulus and tubulointerstitium. Local renin angiotensin system may contribute the progression of tissue injury in IgAN.